While there is no doubt that exercise promotes health, it also increases the generation of free radicals. Free radicals have been implicated in the number of degenerative diseases associated with aging. Vitamin E, an antioxidant, protects cells from oxidative damage during exercise. This research proposes to determine whether the combination of exercise and vitamin E reduces free radical-induced oxidative damage in older adults. The study will utilize a randomized, double-blinded clinical trial to investigate the effects of moderate-intensity aerobic exercise and dietary supplementation of the antioxidant--tocopherol (vitamin E) on markers of free radical-induced oxidative stress in the elderly. Sixty healthy men and women 70 to 85 years of age will be recruited from a retirement center in North-Central Florida. The following baseline measures will be obtained: 1. A monitored, sub-maximal graded exercise test to determine their level of aerobic fitness; 2. Plasma concentrations of tocopherol to evaluate dietary intake; and, 3. Two markers of free radical-induced oxidative stress in vivo, plasma concentrations of malondialdehyde (MDA) and lipid hydroperoxide (LHP). Following baseline testing, subjects will be randomly assigned to one of four groups: exercise + vitamin E (n=15), exercise + placebo (n=15), no exercise + vitamin E (n=15), and no exercise + placebo (n=15). Exercise groups will complete 16 weeks (2, 1-hour bouts/week) of supervised, moderate-intensity, endurance exercise training utilizing treadmill, cycle, and/or stair-climber ergometers. Subjects in the no exercise groups will not exercise and will be asked not to begin any new exercise programs during the study period. Subjects will receive a 16-week supply of either vitamin E (800 IU/day) or placebo capsules. Neither the subjects nor the investigators will know the identification of the real or placebo vitamin until after the data have been collected and analyzed. Subjects will be instructed not to take any other vitamin supplements during the study period. At the end of the study the baseline measures will be repeated. Data will be analyzed by ANOVA to examine differences within and between the four groups in changes in aerobic fitness and serum concentrations of MDA and LHP.